Multiple turret lathe



April 24, 1945; D. E. BENCH ETAL 2,374577 MULTIPLE TURRET LATHE OriginalFiled Sept. 25. 1941 ll Sheets-Sheet l Invmm DAV) E. BENCH NEW! R.CROSBY mm MNIMN 39..

R norm:

P 1945. D. E. BENCH AL 2,374,577

MULTIPLE TURRET LAT'HE Qriginal Filed Sept. 25, 1941 11 SheetsPSheet 2MELWN A. QRObBY HARRY ATOULMWJR 8 \MTHLI r Attomup 3'1 9 3e II 7 5 -43I, a Inventor: 1 38 A DAVID E. BENCH x April 24, 1945.

Original Filed. Sept. 25, 1941 D. E. BENCH ETAL MULTIPLE TURRET LATHE;

/ /K/ i \uq 1 25 26 g I]. Sheets-Sheet 3 April 24, 1945. D. E; BENCH ETAL MULTIPLE TURRET LATHE 11 Sheets-Sheet 4 Original Filed Sept. 25, 1941TTE-.l3. i

' Invmtors DAVID E., BENCH MELV|N R. CROSBY HARRY A. T'OULMlN JR.

Httornup April 24, 1945.

D. E. BENCH ET AL MULTIPLE TURRET LATHE briginal Filed se i. 25, 1941 11Sheets-Sheet 5 April 24, 1945; BENCH 2,374,577

MULTIPLE TURRET LATHE Original Filed Sept. 25, 1941 ll Sheeis-Sheefc 6Inventor's nmno E. scum MELVIN A. CROSBY HARRY A.\'ouLM\u April 24,1945.

D. E. BENCH ETAL MULTIPLE 'I'URRET LATHE Original Filed Sept. 25, 194111 Sheets-Sheet 7 Attgrnn i April 24, 1945. D. E. BENCH ET A]. 2,374,577

MULTIPLE TURRET LATHE Original Filed Sept. 25, 1941 ll Sheets-Sheet 8WORD DAVID E. BENCH MELVIN A. CROSBY 3r HARRY A TOUUMN JR April 24,1945. D. E. BENCH ET AL r 2,374,577

MULTIPLE TURRET LATHE Original Filed Sept. 25, 1941 11 Sheets-Sheet 9.ITEEE.

Inventors DAV) E. BENKH MELVIN A. CROSBY 2,83 2,90 y HARRY A, r ounmmJR.

D. E. BENCH ET AL MULTIPLE TURRET LATHE April 24, 1945.

.' Original Filed s t. 25, .1941

ll Sheets-Sheet l0 R 7 7 )A/A/ eam m n, 5 es. Q: 3 m M i mam I 7 mmm mmmQn mvm Qmn 7 man 7 7 7 3% .v VJ Sm 7 mg n 7 mm Ni mflww om 1 wan 7 0 3 5B 3 Own T I an 1 +3 m3 5m mm l/ ,l. fi Jm QM\ a? U? FF Sn \\\\\\%\\\\\\kfim FM MMP 11 Sheets-Skieet 11 -l-.-. H v ,smlmit A Hm Invento s DAV)E.BENC.H MELVIN RCROSBY HARRY Mouummk V April 24, 1945. D. E. BENCH ETAL MULTIPLE TURRET LATHE Original Filed Sept. 25, 1941 Patented Apr. 24,1945 David E. Bench, Melvin A. Crosby, and Harry A. Toulmin, Jr.,Dayton, Ohio, assignors to The Hydraulic Development Corp., Inc.,Dayton, Ohio, acorporation of Delaware Original application September25, 1941, Serial N0. 412,268, now Patent No. 2,330,859, dated October 5,1943. Divided and this application August 20, 1942, Serial No. 455,466

19 Claims.

This invention relates to a turret lathe ca-' pable of working upon aplurality of work pieces s1multaneously.

An object of the invention is to provide a pluralityof rotatableworkholding devices disposed radially about a turret having a pluralityof work tools adapted tobe brought into working engagement with the workpieces for simultaneous operation upon thework pieces.

Another object of the inventionis to provide a turret lathe capable ofworking upon a plurality of work pieces simultaneously and havinghydraulic means for. moving the toolswith respect to the work pieces. Il 7 Another object of the invention is to provide a turret lathe havinga plurality of work carrying spindles positioned radiallyabouttheturret, said turret being constructed and arranged tosuccessivelyposition a plurality of tools into operative engagement with the workpieces carried by the work spindles.

Another object of the invention is to provide a turret lathe inaccordance with the foregoing object wherein the tools are actuated withrespect to the work pieces by hydraulic means.

Another object of the invention is to provide an automatically operatedturret lathe in accordance with the foregoing objects.

Another object of the invention is to provide a turret lathe having aplurality of headstocks pos tioned radially about a turret which isadapted to carry the tools from one station to another adjacent theseveral headstocks. and means to move the tools with respect tothe workpieces carried by the headstocks. f

It is another object of the invention to provide a turret lathe inaccordance with the foregoing object wherein the tools are carried bythe turret from onestation to another and then are positioned upon asaddle for carrying the tool into operative relationship with the workpiece carried by theheadstock.

Another object of the invention is to provide a-plurality of individuallathe units radially positioned about a turret which is adapted to beoperated to bring the tools carried by the turret into successiveoperative relationship with respect to the Work piece carried in theseveral lathe s whereby a plurality of work pieces is manufacturedsimultaneously. t

Another object of the invention is to provide a turret lathe wherein thetools carried by the turret are moved with respect to the workpiece by.hydraulic means.

Another object of the invention isfto provide a turret lathe whereintheturret carries a plurality of tools into successive operating stationsand hydraulic apparatus is provided for moving the tool from thetturretinto engagement 'with a saddle for carrying the tool into operativeengagement withawork piece.

It is another object of the invention to provide a turret lathe whereinthe turret provides the transporting devicefor a plurality of tools fromone station to another fand saddles carried upon the bed of the lathesupport the tool in its movement with respect to a work piece.

- Another object of the inventionis to provide a turret lathe inaccordance with the two foregoing objects wherein the tools are moved byhydraulic apparatus. t

It is anothenobject of the invention to provide a turret lathe wherein aplurality of tools is moved at a predetermined rate in accordance withthe type of work being done by the tool.

It is another object of the invention to pro- .vide a turret lathe inaccordance with the foretrolling the rate of movement during the cuttingor operating portion of the cycleof movef ment of thetool. It is anotherobject of the invention to provide a turret lathe wherein a plurality ofwork pieces is positioned in a fixed relationship with respect to theturret and the turret is rotated to bring. the tools thereof intosuccessive en- -gagernent with the work pieces for successively .tool;into operative relationship with respect to a work piece, and to provideapparatus for looking the tool to the saddle.

Another object of the invention is to provide an apparatus in accordancewith the foregoing object wherein hydraulically actuated apparatus movesthe tool into operating position upon the saddle and then moves thesaddle with respect to the work piece in the lathe to engage the toolwith the Work piece.

It is another object of the invention to provide an apparatus inaccordance with the foregoing object wherein the means for moving thetool and saddle is a hydraulic means.

It is another object of the inventionto provide an apparatus forcontrolling. the movement of the tool with respect to the work piece ata relatively constant rate regardless of the resistance to forwardmovement made by the tool.

It is another object of the invention. to provide a turret lathe havinga plurality of tools carried. thereupon adapted to be removed from theturret into saddles for carrying the same into oper-- ative relationshipwith respect to a plurality of work pieces positioned radially about theturret.

It is another object of theinvention to provide an. apparatus, inaccordance with the foregoing object. wherein a locking mechanism isprovided between the tool, the saddle and the means for moving the toolwith respect to the saddle.

It is another object of theinvention to provide an apparatus inaccordance with any of theforegoing objects wherein. the tool is broughtinto engagementwith the saddle and to. provide means for accuratelypositioning the tool with respect to the work piece carried in thelathe.

It is another objectof the invention to provide aturret lathe whereinthe tools thereof are hydraulically actuated, 1 a

It is another object of the inventionv to provide means forindependently controlling the movement of a work tool with respect to awork piece in a turret lathe.

It is another object of the invention to provide It is another object ofthe invention to provide a turret lathe having a plurality of radiallydisposed hydraulic cylinders forming the turret for the lathe whereinthe plunger of each of the cyl inders' carries a suitable worktool.

It is another object of the invention to provide a turret lathe inaccordance with the foregoing Iobject wherein the plungers of thevarious cylinders move the tools carried thereby into engagement withsaddles which support the tools when the tools-are in working engagementwith the a respective work pieces.

an automatically operated turret whereinthe turan. automatic control.system for a turret lathe having a plurality of hydraulicallyactuated'tools.

It is another object. of the invention to provide a turret latheadapted. to have a plurality of work pieces positioned therein, theturret lathe also having a plurality of tools hydraulically moved withrespect to the Work pieces when brought adjacent thereto; the movementof each of the tools being automatically controlled at a proper rate ofmovement with respect to the work piece when brought into successiveposition with re.- spect to the several work pieces. 1

It is another object of the invention to provide automatic control overthe movement of the work tools in accordance with the foregoing objectwherein. apparatus positioned adjacent each of the work stationsregulates the movement of tools and is constructed and arranged tocontrol each of the tools at its proper rate of advancement.with respectto the work piece When the respective tools are brought into properposition.

Another object of the invention is to provide a turret lathe wherein thetools are actuated hydraulically in their advancement to and away fromthe work piece and are carriedby the hydraulic apparatus.

It: is; another object of the invention to provide locking means betweenthe tool and the saddle of the turret lathe of the foregoing object.

Another object of the invention is to provide a turret lathe adapted tosupport a plurality of work pieces upon which work is simultaneouslyperformed by means of a plurality of work tools having a turret fortransporting the tools between the several stations and means forremoving the tools from the turret into engagement with the work pieces.

. Further objects and advantages. will becomes apparent from thedrawings and'the following description.

.This application is a division of application Serial No.u4l2,263, filedSeptember 25-, 1941-, now

30. Patent No. 2,330,859; issued October 5, 1943.

In the: drawings:

Figure 1. is a top plan elevational View of a turretlathe constructed inaccordance with the teachings of this invention.

Figure'2 is a longitudinal cross-sectional view of a portion of a lathetaken along line 2--2 of Figure 1, the headstock portion 'of the latheis inelevation Figure 3 is a cross-sectional view similar'to Figure 2but omitting the headstock portion of the lathe and shows one step ofthe locking operation between the work tool and the hydraulic means foractuating the same. H

Figure 4 is a cross-sectional view similar to Figure 3 showing thelocking of the work tool within 'the' saddle provided for carrying thesame in movement with respect to the, work piece.

' Figure 5' is 'a cross-sectionalview similarto Figure 3 showing thework tool in working engagement with the work piece. I

Figure 6 is a transverse cross-sectional View taken substantially alongline 6-6 of Figure 5. Figure 7 is a cross-sectional view similar toFigure 9 showing the locking mechanism in the unlocked position. v yFigure 8 is a horizontal cross-sectional View taken substantially alongline 8-8 of Figure 6. Figure 9 is a longitudinal cross-sectional viewtaken along line 9-9 of Figure 6. showing the locking mechanism in'thelocked position. I

Figure 10 is a horizontal cross-sectional view similar to Figure 8showing. the actuating mechanism for the lock of Figure 9 in theposition for actuating the device as shown in Figure 9. Figure 11 is alongitudinal cross-sectional view similar to Figures '7' and 9, showingthe locking mechanism in the act of unlocking the tool moving memberfrom the tool.

Figure 12 is a horizontal cross-sectional view similar to Figures 8 and10', showing the actuat ing mechanism for the lock in the position foractuating the lock in the manner shown in Figure 11.

Figure 13 is an enlarged cross-sectional view taken along line I3--l.3of. Figure 4 showing the along line mechanism for locking the saddle tothe lathe 'bed." 1

Figure 14 is a cross-sectional view taken along line M-M of Figure 13showing the apparatus for operating the'locking mechanism of FigureFigure 15 is a view similar to Figure. 14 showing the apparatus forlocking the locking mechanism in the locked position.

. Figure 16 is a partial cross-sectional'view similar to Figure 13showing the locking mechanism between the saddle and the lathe bed. inthe unlocked position. 1

Figure 17 is a longitudinal cross-sectional view of the turret of thelathe taken along line ll--ll of Figure 1. p

Figure 18 is a. bottom elevational view taken 18-.48 of Figure 17showing; the Geneva mechanism and the locking means for the same forindexing the turret.

Figure 19 is a schematic diagram electrical system and the'hydraulicsystern for theautomatic operation of the turret lathe.

Figure 20 shows a slightly modified form of the hydraulic system for thelathe.

Figure 21 is a cross-sectional view taken along line .2l'2l of Figure I!showing the means .for controlling the movement of the work tools withrespect to the work pieceswhen the turret transports the tools withrespect to thevarious stations of the lathe. i t Figure 22 shows amodified form of the inven tion wherein the hydraulic cylinders formoving the tools are carried by the turret.

. Figure23 is a view similar to Figure 22 show- I ing a portion of themechanism in cross-section showing vided for by the turret is completed.

The tools are adapted to be removably carried upon theturret so thatthey can beremoved. and placed into engagement with suitable saddlesprovided upon the lathe bed adjacent each of the headstocks. Ahydraulicmotor is provided 'for moving the tools from the turret intoengagement with the saddles and for moving the tool when in the saddleinto workingengagement with a work piece carried upon the headstock; Thetool is replaced upon the turret by means of a hydraulic motor after itsoperation upon the work piece has been completed so that the turret canindex'the tool to the next successive station 1 under control ofautomaticmeans.

to disclose the locking apparatus between the tool 1 carrying member andthe saddle of the lathe. I,Figure 24 is a view similar to Figure23showing the locking mechanism in lock. position.

Figure 25 is a schematic diagram showing .the electrical system and thehydraulic systemior actuating the turret lathe disclosed in Figures 22to 25 inclusive.

Figure 26 is a top plan view of a turret lathe wherein the cylinders arecarried by the turret.

Figure 27 is a cross-sectional view showing a stations of the lathe ismoved in a vertical direction to remove the tool carrying member fromthe saddle of the lathe. t v p Figure 2815 a partial view of Figure 2'?showing the tool in locked position uponthe saddle.

Figure 29' is a cross-sectional view taken along line 29-29 of Figure28. t

FyigureBO is a cross-sectional view of a portion of the saddle of Figure27 showing the locking mechanism between the saddle and the way.

Figure 31 is a longitudinal cross-sectional view of a modified form ofthe turret lathe wherein the tools are completely removed from the lathebed during transportation between the various station s. p I

Figure 32 is a top plan view of the apparatus of Figure 31.

Figure 33 is a cross-sectional view taken along line 33-33 of Figure 31.t

The turret lathe of this invention is constructed and arranged forsupporting a plurality of work pieces upon individual rotating spindlesdis- Or a By radially disposing a plurality of headstocks about. acentrally disposedturretaplurality of individual workpieces can. besimultaneously worked upon to produce articles which necessitate rathercomplicated tooling set ups.- The various head stocks composing thelathe can either be'positionedupon a single casting suitably constructedwith radially disposed beds from a central turret or individual lathe.beds can be radially positioned about a central turret and properlyaligned therewith. p

In this invention the lathe consists of a lathe bed, generally indicatedby the numeral III, which is composed of a plurality of individual bedsIlla radially disposed with respect to one another. The bed II] can be aunit structure, or may be composed of a plurality of individual bedswhich are properly secured together to produce a unit structure. Thebeds Ina are preferably individu-' ally constructed since the sizeof theapparatus lends itself more favorably to theconstruction of individualunits which can be assembled into a larger unit machine.

Each of the beds Hla comprises part of a complete lathe with theexception that the usual tailstock is omitted. 1

Upon each of thev beds 10a there is provided a headstock l I having aworkspindle driven by the conventional mechanism associated with theusual headstock arrangement for lathes and upon which a chuck 2 isadapted to be positioned. The chuck i2 is adapted to carry a work piece13 for rotation with respect to the tools carried upon a central turretI5. It is of course understood that 'while a chuck has been mentioned asproviding the apparatus for holding the work piece 13, any otherapparatus for securing the work piece inposition for rotation withrespect to the work tools can be provided and be suitably mounted uponthe spindle extending from the headstock II.

The headstock H is provided with the usual controls for regulating thespeed of rotation of the spindle and thus controls the speed of rotationof the work piece with respect to the tools carried by the turret: l5for regulating the cut' ting speed forthe various controls. Each of thebeds its is provided with the usual ways l4 upon which a carriage I6 ispositioned for longitudinal movement along the lathe. The carriage Itmay be provided with a square turret I! for producing various transversecuts upon the Work piece l3.

It is to be understood that the carriage l6 and the square turret. H areconventional mechanisms adapted fdr use in lathe work and it istherefore believed that further description ofthis' with all of theusual controls found upon lathes' for controlling cutting speeds,transverse and longitudinal movement of the work tools and othercontrols usually associated with such lathe mechanisms. I

The turret with whichthe lathe beds Illa, are associated consists of ahexagonal base I9 hav-, ing. a centrally located turret supporting post,18. A turret 29- is. provided with a supporting shaft 2| which issecured centrally within. the turret 20. The shaft 2! has an enlargedannular portion' 22 which engages the underside of the turret 20 forsupporting the turret while a nut 23 is threaded upon the shaft 21 forengaging the upper face of the turret 20 and thereby securing the sameto the shaft 2|. post I8 is provided with an upper tapered rollerbearing 24 upon: which the annular enlarged portion 22 is supported andthereby provides. a thrust bearing for the turret 211 for supporting thesame. A tapered roller bearing 25 is provided in the lower portion ofthe turret post It! for guiding the turret shaft 2.1.

The hexagonal bed I 9 has finished faces 26 (as shown in Figure 1'?)against which the lathe beds I'flaabut for positioning the beds Illawith respect-to the base I9 and thus with respect to the turret 2!).Suitable means are provided for securing the beds Illa to the base I9.

The turret 20'is centrally disposed with respect to the lathe beds Illaradially positioned about the hexagonal base I9. The turret 20 comprisesa horizontally lpositioned plate 27 which is provided with a hexagonalshape to correspond with .the hexagonal positioning ,ofthe lathe bedsIlla about the base "3.. Whilethe rot and lathe arrangement yet it is tobe understood that any number of lathe beds can be posiing upon theusageto which the machine is to be The turret plate 21 is provided witha put. T-slot 28 positioned adjacent each of the sides 29 of the turret29,

A tool carrier 30 has a T-shaped head 3| which cooperates with the Tslt21 in the turret 2!! for supporting a tool 32 in position with respectto the turret 29. The cooperation of the T-slot 21 with the T-head 3I ofthe tool carrier 30 permits the tool carrier 30 to be slidably removedfrom the turret 211 for advancement into working engagement with a workpiece carriedv by one of the headstocks H. When the tool carrier 30 ispositioned with the T-head 3-! within the T-slot 21, the tool carrier isarranged for transportation between the stations of the lathe asrepresented by the respective lathe, beds Illa.

Each of the lathe beds Illa is provided with a hydraulic motor 33 havinga double acting piston thereinto which the plunger'rod'34 is attached.The hydraulic cylinders 33 are bolted to their respective lathe beds IDaby means of bolts 35, as indicated in Figure 13. ries a crosshead at theforward end thereof from which there extends a pair of rods 31 securedto the crosshea'd 36 by means of bolts 38. The rods 31 extend toward thecenter of the apparatus upon both sides of the cylinder 33, thecrosshead 36 and the rods 31 thus providing a yoke which is secured to atoolmoving member 39. The tool moving member 39 is slidably carried uponasaddle 40, which saddle is slidablysupported uponthe ways I4 of. thelathe bed Illa. Each of the lathe beds Illa is provided with a saddle4!! and a tool moving member 39 so that the tool carrier can be slidablyremoved from the turret 20 and positioned upon the saddle 40. The saddle40 is provided with a recess42 (see Figure 6) which'cooperates with theways I4 of the lathe bed for supporting and guiding the The turretsaddle 40 during its longitudinal movement upon the'ways 14., A plate 43is secured to the saddle 4D and extends inwardly toward the center ofthe lathe bed for sliding engagement with the under sideof the ways I4thereby preventing the saddle 40 from rising from the ways l4. Thesaddle 40 is also provided with a pair of upwardly extending wallmembers 44 and 44a which form a yoke having a central opening 45. Thewall members '44 and 44a are each provided with a recess 46 and 46ahavingright angular sides for supporting the tool carrier 30 when inposition'therein.

The recess 46in the wall member 44 has a wall 41' which is parallel tothe longitudinal axis of. the lathe bed Illa and has an upper wall 48which is tapered upwardly in thedirection of the position of the toolcarrier 39. The recess 46a is provided with a vertical Wall 49 which istapered outwardly and rearwardly with respect to the position of thetool carrier 30 and an upper wall 50 which is tapered. in the samemanher as the wall 48 of the recess 46. The bottom wall 5| of the yokeformed by the wall members 44 and 44a is parallel with respect to thelathe bed Illa.

invention discloses the use of a hexagonal tur- The tool carrier 30 hasa depending plug member 52 which has the wallsthereof formed to the sameconfiguration as the configuration of the recesses 46 and 46a,heretofore described whereby the bottom wall 5| and the side wall 41provide means for positioning the tool carrier 30 within the yokeprovided on the saddle 49 with respect to the axial center of thespindle carried by the headstock I I. The tapered walls 48. 49 and 59 ofthe recesses 46 and 46a force the plug 52 of the'tool carrier 30 intothe proper position when the tool carrier is moved into the recesses 23and 46a by means of the tool moving member :The tool moving member 39consists of a horizontally positioned plate 53 adapted to slidablyengage recesses 54 and 54a and thereby guiding the tool moving member 39along the saddle 4.0..

A pair of ears 56 depends from the plate 53 and is secured to theplunger rods 34 by means of the bolts 51. The tool moving member 39 isthus connected to the hydraulic motor 33 which; causes reciprocation ofthe tool carrying member 39 upon the saddle 40 when moving the tool-Locking mechanisms are provided for latching and .unlatching the toolmoving member 39 to The plunger 34 car and 12.

the tool carrier 39 and for latching and unlatching the tool carrier 39to the saddle 40. ,The locking mechanism for securing thentool movingmember to the toolcarrier 30 is shown in Figures 6 to 12 inclusive invarious positions during the latching and unlatching of the tool movingmember 39 to the tool carrier 30. The plug member 52 of the tool carrier30 is provided with a reduced diameter portion 58 extending rearwardlythereof. A recess 59 is provided in the lower edge of the reduceddiameter portion 58 andv con'sists of a vertical forward face 60 and arearwardly tapered face 6|.

The reduced diameter portion carrier 30 is adapted to slidably engage abore 62 provided in the tool moving member 39. A vertical bore 63communicates with the bore 62. A locking pin 64 is slidably positionedwithin the bore 63, which pin is provided with a roller 13 suitablypivotally carried upon the lower end of the pin 64. in

The pin 64 is adapted to be reciprocated vertically into and out of therecess 59 provided in the reduced diameter portion 58 of the toolcarrier 30 by means of a horizontally positioned actuating rod 65slidably carried within a bore 66 positioned transversely of the plate53.; Rollers 61 are pivotally carried upon opposite ends of the rod 85for engaging the recesses 54 and 54a provided in the saddle 46, The rod65 is provided with a recess 88 having an angular face 69 and ahorizontal bottom wall 10. The roller 13 carried upon the pin 64 engagesthe faces of the recess 68 for actuating the pin 64 vertically upontransverse reciprocation of the actuating rod 65.

To obtain reciprocation of the actuating rod 65 the recesses 54 and 54apositioned within the saddle 40 are provided with suitable guide tracksfor the rollers 61 carried upon the actuating rod 65. A guide track H isprovided in the face of the recess 54 and extends rearwardly of thesaddle 49. A similar guide track Ha is provided in the faceofthe recess54aand extends forwardly of the saddle 40. The guide track II has anangularly disposed face 12 which connects the bottom of the track IIwith the face of the recess 54. The guide track Ha is provided with asimilar angular face 12a for connecting the bottom of the track- 1 lawith the face of the recess 54a. The angular faces 12 and 12a aredisposed with respect to one another in such a relationship that uponforward movement of the tool carrying member 39 by meansof the hydraulicmotor 33,

the roller 6'! on the left end of the actuating rod will engage the face12 to shift the rod 65 in a rightward direction as viewed in Figures 8,When the actuating rod 65 shifts to the right the angular face69provided in the rod 65 engages the roller 13 to move the pin upwardlyinto engagement with the iecess 59 provided in the reduced diameterportion of the tool carrier This locking movement of the pin 94 is intimed relation with respect to the movement of thetool moving member 39with respect to the tool carrier 39. As viewed inFigures 7 and 8, thetool moving member 39 is disengaged from the tool carrier 30. At thistime the tool carrier 30 will betcarried by the turret by means of theT- head 3i in the T-slot 21 in theman'ner shown in Figure 2. Therelationship between the tool moving member 39, the tool carrier and theyoke of the saddle 40 (as shown in Figure 2) issuch that the toolcarrier is ready to bemoved into en-,

gagement with the yoke of the saddle 49 after 58 upon the tool.

When the reduced diameter portion 58 has made a substantial entry intothe bore 62 the actuating rod willshift in the rightward direction (asseen in Figure 8) to move the pin 64 upwardly intoengagement with therecess 59 provided the reduced diameter portion. By the timethe rod 65has completely shifted totherightthe-pin 64 will have the forward facethereofin engagement with the forward face lifl ofthe recess 59 therebysecurely locking andpositioningthe tool moving member withrespectto thetool carrier 38. This position is shown in Figures 9 and 10.

Continued forward advancement of the tool carrier moving member 39 wil1slide the ,T -head 3 l of the tool carrier 39 within the T-slot 21 uponthe turret 29 so that the plug 52,upon the tool carrier 30 will enterthe recesses46 and 46a provided in the yoke upon the saddle 49, ,Whenthe plug (52 substantially completes its entry into the yokeprovided onthesaddle 40 a locking mechanism is actuated for lockingthe toolcarrierwithin thesaddle 49. s H t t This locking mechanism; consists of abell-- crank lever 14 carried upon a pivot pin 15, the: lever beingpositioned within a recess I6 plOvided in the forward edge of thesaddle40. Oneend of the bellcrank lever 14 is providedwith a roller ll whilethe opposite endthereof hasa 5191318 which engages a pin 19 carried upona locking pin 89 slidably positioned within a bore 8| verticallyarranged Within the saddle 40 and adja cent the median pointpf the yokeprovided by the walls 44 and 44a. 4

The saddle 49 is normally held inllocked engagement with the ways 4| ofthe lathe bed I9 a to prevent movement of the saddle until the plug 52of the tool carrier 39 hasimade complete entry into the yoke-provided onthe saddle 49. The saddle locking mechanism is operated concomitant withthe locking operation of the tool carrier locking mechanism so thatthesaddle4fl will be unlocked from the ways .14 at the instant the toolcarrier islockedto the saddle 40; i

The saddle locking mechanism is operated means of the tool carrierlocking pin 80 l (as shown in Figures Band 16). The saddle lockingmechanisms consist of a pair of. bellcrank levers 82 pivotally mountedupon the pins 83andp0sitioned within a recess 84 (provided in the saddle40. One end of the bellcrank 93 engagesa pin 85 carried upon the lowerend of the locking pin 89. The opposite end of thebellcrank lever 82engages pins 86 carried upon the saddle locking pins 81 slidablypositionedwithin bores 88 provided within the saddle 40. The saddlelocking pins 81 have collars 89 secured near the ends thereof.Compression springs 99: are positioned around the pins 81 and have oneend thereof in engagement with the collars 89 while the opposite endengages a shoulder 9| provided bythe'enlarged bore 92 positionedcoaxially with the bore 88 Each of the ways I4 has a recess] 93Lintowhich the ends of when locking-the sadi carrying member 39 is therebylocks the tool carrier to the saddle yoke. After the hydraulic motor 33has moved the tool carrier moving member 39 into locking engagement withthe tool carrier (as shown in I thepin l5 and thereby vertically movethe tool carrierlocking pin 80 upwardly into the recess 94 provided inthe plug 52. As the plug 52 makes complete entry into the saddle yokethe locking pin 89' rotates the bellcrank levers 82 of the saddlelocking mechanism about their respective pivots 83 todraw the lockingpins 81 inwardly and out of engagement-with the locking recess 93provided the ways 4I,- as shown in Figure 16. The tool carrier 39 is nowpositionedrigidly in the saddle so that the hydraulic'motor 33 can movethe tool 32 into working engagement with the work piece i3 carried uponthe spindle extending'from the headstock II. The rate of for-' wardadvancement of the tool '32 with respect to the workpiece I3 is underautomatic control in amanne-r-wh-ich will hereinafter be morespecifically described.

After the workoperation' has been performed on the work piece thehydraulic motor is reversed i-n-its movement, in.a manner whichbedescr-ibe'd; for retracting the tool from the Work piece, removing thetool 'carrier'from the saddle, simultaneously placing the tool carrierupon the turret andthen disengaging the tool carrier moving member fromthe tool carrier to reposition the elements as disclosed in Figure 2,whereby the turretcan be indexed and the next successivetoolbroughtin-to alignment with the workpiece for the next successiveoperation.-

Duringthe initial portion or the retraction movement of the-saddle, toolcarrier and-tool carrier moving" member "the elements remain m lockedengagement, the-saddle-and the tool carrier being retained in lockedengagement due to the'fact that the-ends of the rods 81 engage the innerfaces 99 of the ways M. When the saddle 40 reaches its initial positionupon the ways I4 of the lathe b ed- I'Dathe rear end of the-saddle- 4-0.

- strikes a stopprojection 981 (see-Figure 17 whereby the saddle 40 ispreventedirom turther retraction movement. The tool carrier and the toolcarrier movin'gmember are continued in their retraction movement bymeans of the hydraulic motor-33, these elements remaining inlockedposition and the'moverneht of the tool carrier with respect to thesaddle unlocks the carrierfirom the saddle. Theforward angular face 95of the recess 94 inthe plug 52 of thetool carrier 39 engages the roller91 on the locking pin 80 of the tool carrier locking-mechanism wherebythe locking pin 89 is caused to move downwardly, as 'viewed in FigureI4. This movement ctthe locking pin 99.

causes the saddle locking'pi-n's- 87 to move outwardly and positiontheir endswithin the recess 93 providedinthe'ways I4 of the lathe bed.The compression springs 90 aid the movement of the saddle l'ockingpins81 to forcethe same into the recess 93 when the saddle 40 1s in itsproper position upon the lathe ways I4. The tool: carrier 39:

is thus gradually unlocked from th esaddle 40 and thesaddle I-Il-lockedto the ways I4.

The tool carrier'andthe tool carrier moving member continue theirretraction: movement-due to operation of the hydraulic motor 33. theforward end of the plug'l52 is removed. from.

When.

-- carrier; moving member 39.

is prevented from further retraction movement. d When this position isreached the "rod for actuating the locking mechanism between the toolcarrier 30 and the tool carrier moving member 39 has been brought into aposition whereby the ends thereof are adjacent the angular faces 72and'iZa in the guidetracks II and Ha provided in the saddle 40. Theright hand end of the actuating rod 65 engages the singularly-disposedface/12a, to "cause the rod 65 to shift in a leftward direction (asviewed in Figure 12) whereby the locking pin 64 provided in the toolcarrier moving member 39 is disengaged from the recess 59 provided inthe reduced diameter portion '58 of the tool carrier-30. The toolcarrier moving member 39 is thus released fromthe tool carrier 3d topermit the same to retract-to the position shown in Figure 2 so that theend of the reduced diameter portion '58 is free of the tool Themechanism is then ready to *be indexed to bring the next suc-' cessivetool into alignment with the spindle of the headstock II.-

The indexing mechanism for the turret. 2'0 consists of a Geneva wheel Isecured to the lower end of the turret shaft 21 by means of the bolt IBI(-see Figure 17), An electric motor I02 drives adouble acting arm I03through means of a gear head I94 for actuating the Geneva wheel I99. Alimit switch I 05 controls the opening of the circuit to the electricmotor I92 at the end ofthe travel of the arm I03; The'Geneva wheel II'IBis locked in position by means of a. locking pin I06 which isslid'ablymounted in a casing I'IIL A compression spring I08 urges the pin I96into engagement with the slots I09 of the Geneva wheel 'I90. An electricsolenoid I ID has an armature 'III connected to the pin I96 by means ofa link II2 anda bell-crank I43 for reciprocating the'locking, pin M6 forremoving the pin 106 from the slots 19. 1 The plunger rod IM or thelocking p'inl'flfi' actuates a pair of limit switches I I5 and H6 forcontrolling operation, of the indexing. mechanism as will be hereinafterdescribed. h, The hydraulic system for controlling the -movement of thetool carrier throughout its cycle-of operation (see Figure 19) consistsof the hydraulic motor 33 .previouslyv referred to. Fluid for servingthe hydraulic motor 33 is removed from the reservoir M1 by means of apump H8 driven: by a suitable electric-motor, Theplimp H8 ispro videdwith a delivery condui-t M9 and a return conduit IZO. As by-pass valveI-2-I is provided. between the delivery and return conduits; 119' andI29 to control the maximum pressure within the delivery conduit 119.,-The system'may he. of

this type using a by-pass relief valve or. the-pum can be of thevariable delivery type wherein. the

ump moves to neutral upon the: development or a predetermined maximumpressure.

A 4-way valvelfl is connected with adel ivery consisting oi a checkvalveI'ZI? and a choke-valve I21. The fluid passing through, theconduitI25 actuates the fluid motor to retractthe saddle 40, the toolcarrier 30 and the tool carrier moving member39 withrespect to theheadstock end of the lathe. i

The opposite end of the hydraulicamotor 33 receives fluidthrough theconduits I28 and I29, a valve I30 connecting the conduits I28 and I29,The valve I30 consists of a plunger rod I3I having a piston head I32adapted to shut oil the flow of fluid betweenthe conduits I28 and I29after a predetermined forward motion of the tool carrier 30 to shift thefluid supplyto the fluidmotor through a by-pass system. I

The by-pass system consists of a constant flow control mechanismcomprising a flow control valve I33 and a choke I34. The choke valve I34is adjustable in the manner hereinafter described.

The flow control valve I33 has an inlet con.- duit I35 and anoutletconduit I36, whichoutlet conduit is connected to the inlet of the chokeI34.

The choke resists passage of fluid therethrough to the outlet conduitI37. The flow control valve I33 has a control conduit 138. connected toone side of the valve I33 which conducts pressure from the'conduit I31to one side of .the valve I33.

, A second control conduit I39 is provided on the valve I33 and conductspressure from the conduit I36 to the valve I33. Theflo w controlapparatus herein described is of the typemore fully dis: closed anddescribed in Figure 1 of the patent to T. L. Farnham #2146537,patentedFebruaryT, 1939. The valve system controls the flow of fluidfrom the inlet conduit I35 to the discharge conduit I31 at a constantflow rate regardless ofthe pressure developed inthe conduit I31 due tothe increased pressure developed in the. conduit by the additionalresistance met by the hydraulic motor in advancing the apparatusactuated thereby upon the work piece. A constant flow control, such asthe Farnham control, provides an apparatus wherein the rate of forwardrnovement of the work tool is alwaysconstantregardless of the resistancemet by the work tool. a

A check valve I40 is connected between the conduits I31 and I28 which.byepasses fluid around the flowpcontrol valve I33 and the choke 134during the return stroke of the-hydraulic motor when fluid is beingadmitted to themotor through the conduit I25..

The valve I30 of the hydraulic system heretofore described comprises apartof the apparatus -for controlling the rateof advancementof the toolwith respect tothe work piece... When the valve I30 is in the positionshown .in Figure 19, the full flow of hydraulicfluid from the pump! isdirected to the right hand end of the motor 33 to produce a rapidforward motion ofgthe motor and thereby causethe tool carrier ;30 to beadvanced rapidly into engagement with the saddle 40 and approach itsworking position with respect to the WOI'kj piece. At a predeterminedpoint in the forward travel of the tool. carrier the valve I30 isshifted in .a leftward direction so that the head l32ispositionedbetween the conduits I28 and I29 thus closing these conduitsto flow of fluid. The fluid must then flow through the by-pass systemwhichnreduces the flowrate to that desired for the proper forward motionof the. worktoolwith respect to the workpiece; The flow rate iscontrolled by the choke valve I34 which is. adjustable to meet varyingconditions. of tool movement. .Asuitable connecting means,;indicated bythe dottedlines I4I of Figure 19,1interconnects the tool carrier 30 witha control member I42 reciprocable upon the plunger rod I3! of the valveI30. When th control member I42 is moved forward a collar I43 providedon the plunger rod I3I is engaged to shift the valve I 30 as heretoforedescribed. Suitable springs I44 positioned within the member I42 providesufficient friction upon the collarI43 to shift the valve I30 bypermitting the member I42 to pass over the collar I43 after the valveI30 has shifted to permit forward advancement of the work tool. Asimilar operation is performed when the tool is retracted. Thewinitialrate ofmovement of the tool away from the work piece is governed bytheby-pass system until themember I42 shifts the valve I30 to open theconduit system I28, I29. During the initial movement of retraction ofthe tool fluid from the right hand end of the cylinder 33 passesthroughthe check valve I40.

The machine of this invention provides for several operations upon awork piece by various tools. It iswell known that each tool requiresadifferent speed of operation from other tools and therefore some meansmust be provided for changing the speed of advancement of the saddle 40and the work tool carried by the tool carrier 30 with respect to thework piece so that as'successive tools are brought into proper workingrelationship with the work piece that their speeds of advancementuponth'e work piecewill be-the most favorable speed for the particulartool. v

The choke valve I34 must therefore bereadjusted as to the flow controlrate throughit each time a new tool is positioned in workingrelationdisclosed in Figure 21 and consists of a plurality of individualcams I41 pivotally mounted upon the plate by means of the pivot pinsI48. An adjusting screw I49 is provided for each of the cams I41 and isin threaded engagement with a boss I50. A tension spring I5! retains theinner surface of the cam I41 in engagement with the adjusting screw I49.The adjusting sc-rew I49 positions the outer surfaceIEIof the camsrelative to thelchokevalve I 34'.

The choke valve I34 is shown in cross section in Figure 21 and consistsof a body I52 having a plunger I53 extending therefrom. A piston. I54 isslidably positioned within a cylinder I55 provided in the body I52. Acompressionspring I56 degree of restriction offered by the choke valveI34 when the cam engages the control rod I 53 of the choke valve. Eachof the tool stations is provided with a cooperating cam I41 and sincethe cams I41 rotate with the tools when rotated by the turret 20 it maybe seen that the choke valve I39will be adjusted by the cams I47tocontrol the rate of flow offiuid therethrough and thus the speed offorward advancement of the tool with respect to the work piece. Each ofthe tools thus has its own controlled speed which can be readilyadjusted to meet varying conditions. I I

- 'ing cycle.

In Figure 20 there is disclosed a modification of the hydraulic systemfor regulating the flow of fluid to the hydraulic cylinder 33. In thismodificationra pressure regulating Valve I58 "is positioned between thechoke valve I34 and .the fluid conduit I28. The pressure regulatingvalve I58 controls the pressure in the conduit I36 at a substantiallyconstant level so that a predetermined pressure difi'erential isprovided across the choke valve I34. Since the resistance made by thework tool is substantially constant-the back pressure in the conduit I31will be substantially constant and thereforethe pressure difierentialacross the choke valve I34 will be constant whereby a constant forwardmotion of the work tool across the work piece is established.

The electrical system for controlling the automatic operation of theturret lathe is disclosed in Figure 19. A plurality of limit switchesI59 is placed in series electrically, each of the limit switches beingassociated with one of the tool carrier moving members 39. These limitswitches I59 are closed when the tool moving member 39 is in its ful1retracted position and are opened by means of the springs I60 when thetool moving member 39 is in a forward position. A relay I6I controls theelectrical energization of the Geneva wheel locking solenoid -I I andthe operation of the solenoid I62 of the 4-way valve- I22. The relay I61is supplemented by means of a relay I63 which conditions the electriccircuit for the solenoid I62 of the 4-way valve I22. A limit .switch I64is positioned adjacent the forward, limit of the forward stroke of thetool carrier 30 or the saddle 40 for initiating'the retraction stroke ofthe tool carrier 30. p

The electrical system, as shown in Figure 19, has the elements thereofpositioned in their normal deenergized positions with all of theelements at rest after the completion of the retraction stroke of thtool moving members 39. The system is in readiness for the initiation ofan index- The initiation of the indexing cycle can be eitherautomaticallyor manually controlled. 'A selector switch I65 is providedfor controlling the condition of the electric circuit for either manualor automatic operation and as shown in Figure 19 is in position formanual operation of the initiation of the cycles of operation of the Yturret lathe. A push button switch I66 is provided for manuallyinitiating the energization of the control circuit.

To begin acycle of operation of the turret lathe the push button switchI66 is closed whereby an electric circuit is made from the power line I61 through the line I68, the limit switches I59, the line II69, I thepush button switch I66, lines I1I,, I12, therelay I6I to the power lineI13. The solenoid .I6I is thus energized to close the'blades I14, I andI16 upon their respective contacts andto open the blade I11 from'itscontacts. As

soon as the relay I6I closes the blade I16 upon its contacts a holdingcircuit is established for the relay I6I throughthe line I18, the relayI6I, the line I19, the blade I14, the line I80, the limit switch I05,the line I81 to the power line I61. This holding circuit is maintained,until the indexing cycle is under way.

. The blade I15 closes an electric circuit to a relay I 'from the. powerline I13 through the line I82, the blade I15, the lines 183,, 2.02, therelay 20I, the line, I69, the switches I59 andline I68 through the powerline I61.""'I'he relay 20] is thus energized to open blade 203 from itscontacts and to close blade 204 upon its contacts. The blade 1203 thusbreaks the electric'circuit from :the selector switch I65 and. the pushbutton switch I66 to the relay I 6-I. to prevent any subsequent controlover this relay. The blade 204 provides a holding circuit for the relaf20I which is retained until one of the switches I59 breaks circuit. Assoon as one of the limit switches I59 is opened the relay 2 0Ireconditions the initiating circuit through the push button :switch I66or the selector switch. I65 to permit initiation of the next cycle ofoperation.

.At the same instant the blade I15 closes a circuit from the power lineI13 through the line I82,

the blade -I15,the lines I83, I84 to the relay I63 and through the lineI85 to the power line I 61. The relay 163 thus closes the blades .I86andI81 upon their respective contacts. The blade I86 establishe .a holdingcircuit for the relay I63 from the power line I13 through the line I 88,the

cuit to the Geneva wheel operating solenoid H0 from thepower line I13through'the lines I82, I91, the blade I16, the line I92, the solenoid II0 and the lines I93, I94 and I85 to the power line Hi1. Energization ofthe solenoid IIO removes the locking pin I06 from the Geneva Wheel I00.The movement of the locking pin I06 causes the limit switch II6 to closeand the limit switch I I5 to open. Closure of the limit switch II5establishes an electric circuit to the motor I02 of the indexingmechanism from the power line I13 through the line I93, the motor :I02,the line 194, the switch I16 and the line I85 to the power line I61.

The motor I02 drives the arm I03 of the Geneva mechanism for startingthe Geneva wheel in its indexing motion. Soon after the arm I03 hasstarted its movement it contacts the limit switch I05 to open the same.When the'limit switch I05 opens the holding circuit the relay I'6I isopened whereby the relay I6I is deenergized and the "blades 114, I15 andI16 are removed from'their contacts while the blade I11 closes upon itscontacts. When the relay I-6I becomes deenergized the electric circuitestablished to the Geneva wheel solenoid I I0 is broken whereby thelocking pin I06 is forced into engagement with the Geneva wheel by meansof the spring I08. The locking pin I 06' however cannotprevent theGeneva wheel from continuing its indexing motion since it cannot enterthe groove I09 until the arm I03 has brought the groove 109 into properrelationship with the locking pin I06. The switch I I6 remains closed tomaintain circuit to the electric motor I02 until the indexing motion iscompleted and .thelocking pin I06 entersthe groove I09.

Whenfthis operation occurs the switch H6 is opened to .breakcircuit tothe electric motor I02 andthe switch I I5 is closed to make circuit tothe solenoid I62'of the 4-way valve I22.. As previously mentioned relayI63 has been energized when the relay I6I was closed. The relay I63established its holding circuit as previously described and the blade181 is closed uponits contac'ts. Assoon as the switch II 5'is closed bythe locking pin 106 an electric circuit is established to theisolenoid"I62 :01 the 4-way'valve I22 from the power line I13 through the lineI95, the blade motor 33.

The hydraulic motor 33 will carry the tool carrier through a forwardstroke in the manner here tofore described. When the tool carrier 30 andthe saddle 40 reach the limit of the forward stroke the limit switch I64is engaged to open the hold ing circuit previously establishedtherethrough for the relay I63.

The relay I63 is deenergized whereby the blades I86 and I81 open circuitthrough their contacts and thereby deencrgizing the solenoid I62 of the4-way valve I22. Deenergization of the solenoid I 62 permits the 4-wayvalve I22 to be returned to its initial position by means of the springI 99 whereby hydraulic fluid is then directed from the conduit I23 intothe conduit I25 causing a retraction stroke of the hydraulic motor 33and thereby carries the tool carrier 38 and the saddle 48 throughout aretraction stroke and releases the tool carrierfrom the saddle and thetool carrier moving member 39 from the tool carrier 30 in the mannerheretofore described. r

c When all of the tool carrier moving members 39 are in their fullretracted I position the limit switches I59 will be closed and thecircuit is then in condition for another cycle of operation. As

shown in Figure 19 the circuit must be reenergized by means of the pushbuttonswitch I66 since the selector switch I65is in series therewith.

If the selectoris in the cycle of operation will be automaticallyrepeated since the relay 29I is now in the deenergized position with theblade 263 closed upon its contacts.

In Figures 23 to 26 there is shown a modified arrangement wherein thehydraulic cylinders for moving the tools into engagement with theworkpieces are carried by the turret. Also, a modified arrangement of alocking device between the tool carrier and the saddle is shown forlocking the I members together for suitably guiding the tool in itsworking relationship with respect to the work piece carried in thespindle of the lathe. Figures 25 and 26 show iii-diagrammatic form therelationship of the hydraulic cylinders with respect to the turretforbeing supported thereby and with respect to the saddle supported bythe bed of I provided for moving each of the work tools into engagementwith the workpiece. The motors 2I0 are radially disposed within a turrethousing 2 suitably carried by a turret post 2I2.

Each hydraulic motor 2|I.'I is provided with a reciprocating plunger 2 I3 which supports a tool carrier 2I4 for holding a tool 2I5. The toolcarrier 2 I4 is provided with a plurality of rods 2I6 which extendrearwardly toward the motor 2 In and are adapted to engage a pluralityof cooperating bores 2" provided in the housing for the motor 2I0.

When the rods 2I6 enter the bores 2I1 the tool series with the eenteetzuo proper alignment with the saddle 220 carried upon the bed 22I of thelathe. The saddle 22llis guided upon suitable ways 222 provided upon thelathe bed 22I for carrying the tool carrier 2I4 into workingrelationship with respect to the work piece carried by the lathespindle. The tool carrier 2 I 4 is provided with a wedge-shaped head 223which is adapted to enter a wedge-shaped opening 224 -inthe saddle 228so that the angular surface, 225 of the wedge-shaped head 223will engagethe angular surface 226 of the wedge-shaped opening in thesaddle 220.Positioning of the wedge-shaped head 223 within the wedge-shaped opening224 locates the tool 2I5 during itsworking stroke. I

In order to lock the tool carrier 2 I4 tothe sad-v dle 229 a lockingplunger 221 is positioned within a vertical bore 228 withinthe saddle220. The plunger 221 isprovided with a reduced diameter portion 229which slidably engages a bore 230 in a plug 23Irwhich closes'one end ofthe bore 228. A pin 232 extends through the plug 23I and through a slot233 provided in the stem or reduced diameter portion 229 of the plunger221 whereby the plunger is prevented from rotation. A compression spring234 is positioned between the plug 23I and the plunger 221 forurging theplunger in an upwardly direction.

The upper end of the plunger 221 engages a plate 235 slidably positionedwithin a groove or track 236 within the wedge-shaped opening 224provided in the saddle 229. The plate 235 has a pin 231 extendingtherefrom into a slot 238 provided adjacent the wedge-shaped 0pening224. The lower end of the pin 231 carries a piston 239 slidablypositionedwwithin a bore 240 provided in the saddle 220. A compressionspring 24I urges thepiston 239 in a rightward direction,

as viewed in Figure 23, and thus normally pushes issecured to the stem229 by means of the nut 259. I

The rollers 242 engage an inclined surface-243 provided upon the lathebed 22I and adjacent each of the rollers 242. Each of the decliningsurfaces243 terminatesin arcuate surfaces 244 forming alhook into whichthe rollers 242* are forcedvto lock the saddle 220 in position upon thelathe bed 22I, as shown in Figure 23.

The locking mechanism just described operates in the following manner.When the hydraulic motor 2 I 0 moves the tool carrier 2 I4 forwardly tocause engagement of the wedge-shaped head 225 with the wedge-shapedopening 224, a shoulder 245 provided upon the lower surface of thewedgeshaped head 225 engagesthe plate 235 to move the samein a leftwarddirectionagainst the compression of the spring 24L As the wedge shapedhead 225 approaches its completely entered position inthe wedge-shapedopening 224 a bore 246 carrier 2 is retained in its proper workingposition for entry into engagement with the work r piece carried by thespindle of the lathe and in provided in the head 225 is brought intoalign ment with the bore 228 provided in the saddle 220 (see Figure 24).The bore 246 is provided with tapered side walls to engage a taperedsurface 241 provided on the plunger 221. The first movement of theplunger 221 is a verticall movement to permit the roller 242 to bedisengaged from the lower portion of the arcuate surface 244 formed onthe bed 22I. The vertical movement of the roller 242 is permitted by thearcuate surface 248 which joins the arcuate surface 244

